Merge pull request #3802 from lambdageek/dev-reference-attr-take3

[loader] Re-enable the reference assembly attribute check

diff --cc mono/metadata/assembly.c
Simple merge

diff --cc mono/metadata/class.c
Simple merge

diff --cc mono/mini/method-to-ir.c
Simple merge

diff --cc mono/mini/mini-exceptions.c
Simple merge

diff --cc mono/tests/Makefile.am
Simple merge